Watch-bezel with unbreakable concavo-convex tensional crystal.



B. 0. AMES.

WATCH BEZEL WITH UNBREAKABLB GONGAVO-GONVEX TENSIONAL CRYSTAL. APPLICATION FILED FEB, 16, 1915.

1,1 33,780. Patented 30, 1915.

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0F BRISTOL, CONNECTICUT, A. CORPORATION. WATCH-BEZEL WITH UNBREAKABLE CONCAVO-CONVEX TENSIONAL CRYSTAL.

Application filed February 16, 1915. Serial No. 8,603.

To all whom it may concern:

Be it known that I, BLISS C. AMns, a citizen of the United States, residing at Waltham, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Watch-Bezels with Unbreakable Concave-Convex Tensional Crystals; and I do hereby declare the following, when taken in connection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this application, and represent, in.

Figure 1 a front view of an unbreakable crystal constructed in accordance with my invention and shown prior to being placed under tension. Fig. 2 a plan view thereof. Fig. 3 a View on an enlarged scale in vertical sect-ion of a watch bezel and unbreakable crystal constructed and applied in accordance with my invention.

The Watch crystals in common use throughout the worldare made of glass and are concavo-convex in form for the clearance of the hour and minute hands. Such crystals are not only expensive in themselves, but to their initial cost a large per centage must be added by the watch-manufacturer to cover the breakage of crystals in fitting them into watch-bezels in the first instance. Moreover, glass crystals as sup-' plied by foreign makers to the American trade, vary so much in diameter that they are commonly graded in from 15 to 20 sizes to all of which watch-bezels must be conformed which is a source of considerable expense both as to construction and handling. Furthermore, in fitting a glass crystal into the groove formed to receive it in the benzel, the thin edge of the crystal is extremely liable to break off in particles and work into the movement. From. the frequency with which watches are found to be stopped by such particles of glass, the same have acquired the name of stoppers.

The ob'ect. of my invention is to avoid all of the above and other objections and to produceat a low cost an unbreakable or elastic watch crystal requiring no grading and not splintering so as to produce Stoppem I. I

-With these ends in view, my invention consists in a watch bezel providedwith an unbreakable elastic concavoeconvex crystal maintained 111 tension by the bezel.

In carrying out my invention as herein undercut groove 4 so that the crystal 2 cannot be introduced into the groove of the bezel until it has been nominally reduced in diameter by springing it into concavo-con: vex form. When so sprung and still under tension, its beveled edge is introduced into the groove 4 after which-the means applied to the disk to spring it into concavo-convex form are released. The disk then immediately recovers itself sufficiently to have its beveled edge firmly seated in the bottom of the groove 4, being thereafter maintained in concavo-convex form in the bezel under sufficient tension to hold it in place and to at all times compensate for contractions and expansions in the disk due to-variations in temperature caused by the heat of the body or otherwise, as well as the shrinkage due the disk and the user of the watch will have y no occasion to have the crystal replaced.

Moreover, the edge of the disk being very tough will not crack off at the time of insertion into the groove in the bezel so that no bafiiing stoppers will be produced.

My improved unbreakable tensional crystal reduces'the initial cost of the watch to the manufacturer and avoids the cost of broken glass crystals to the user. Inasmuch as'the disk is always under tension, its edges will always be crowded into the groove of the bezel and therefore so tightly fitted thereinto as to prevent the entrance of any dust or other foreign particles into the watch around the edge of the disk.

I am aware that the use of celluloid in the place of glass for watch crystals has been proposed and I do not broadly claim the idea, but only my specific crystal made larger in diameter than the groove in the bezel and thrown into concavo-convex form for its introduction into and retention in the bezel.

I claim: 1

The combination with a watch-bezel formed with an annular groove, of a celluloid watch-crystal larger in diameter than the diameter of the said groove into which BLESS G.

Witnesses:

JOHN J. FLYNN, MARY D, Anna 

